As one of semiconductor manufacturing apparatuses, there has been known a thermal processing apparatus that performs a thermal process such as a CVD (Chemical Vapor Deposition) process to a number of substrates to be processed such as semiconductor wafers (hereinafter referred to also as “wafer”). The thermal processing apparatus includes a carry-in area into which a container containing a plurality of wafers is carried by an automatic conveying robot or an operator, and a loading area as a transfer area in which the wafers in the container are transferred to a boat as a substrate holder so as to be loaded into and unloaded from a thermal processing furnace.
In such a thermal processing apparatus, in order that an atmosphere of the loading area is made cleaner than that of the carrying-in area and that generation of a natural oxide film on a wafer is prevented, it is preferable that the carrying-in area on the atmospheric side and the loading area are separated from each other by a partition wall, and that the loading area is filled with, e.g., nitrogen (N2) gas so as to provide an inert gas atmosphere. In this case, in order to restrain wafers from being contaminated by particles, there is preferably used a sealable container (FOUP; front port unify pod) having a lid that is detachably attached to an opening formed in a front surface of the container.
FIG. 9A shows a state in which the sealable container is in contact with the aforementioned partition wall. In FIG. 9A, the reference number 5 depicts the partition wall separating the carry-in area S1 and the loading area S2 from each other, 25 depicts an opening formed in the partition wall 5, and 27 depicts a door that can open and close the through-hole 25. A FOUP 3 is placed on a table (also referred to as “transfer stage”) 7 disposed in the carry-in area S1. Then, the FOUP 3 is held by a locking mechanism 19, and thereafter the FOUP 3 is pressed toward the partition wall 5 by a contact drive part such as an air cylinder 16, so that a peripheral portion of an opening 11 of the FOUP 3 is brought into contact with a sealing member 26 arranged on a peripheral portion of the through-hole 25. After that, a lid 12 of the FOUP 3 is opened.
The door 27 is provided with a lid opening/closing mechanism 13 for opening and closing the lid 12. The transfer stage 7 is slidably supported on a stand 51 via a slide guide 52 in a fore and aft direction (i.e., in a right and left direction of the plane of FIG. 9A). A plurality of positioning pins 8 for positioning the FOUP 3 are projectingly disposed on the transfer stage 7. The locking mechanism 19 is arranged on the transfer stage 7, and is adapted to hold the FOUP 3 by engaging an engagement member 18 of the locking mechanism 19 with an engagement recess 17 formed in a bottom part of the FOUP 3.
In order to open the lid 12, the lid 12 is opened by the lid opening/closing mechanism 13, with the door 27 being closed. In this case, it is preferable that, after an atmosphere in the FOUP 3 has been replaced with nitrogen gas by a nitrogen-gas replacing means, not shown, the door 27 and the lid 12 are retracted from the through-hole 25, and than wafers W in the FOUP 3 are loaded into the loading area S2. This is because increase in a concentration of oxygen in the loading area can be restrained. Such a technique is described in JP11-274267A.
When the lid 12 of the FOUP 3 is opened, the FOUP 3 is subjected to a differential pressure between an internal pressure of the loading area S2 and an atmospheric pressure of the carry-in area S1. However, the above-described thermal processing apparatus is not so resistive to such a differential pressure. Thus, as shown in FIG. 9B, there is a possibility that the FOUP 3 is swayed by the differential pressure, and/or that the FOUP 3 is inclined and displaced from the through-hole 25 of the partition wall 5, which invites the following problems.
Namely, because of the displacement of the FOUP 3, there may occur mapping error of waters W and transfer mistake of the wafers W. In addition, the concentration of oxygen in the loading area S2 may be increased by leakage of the nitrogen gas. In this case, since the atmosphere of the loading area has to be again replaced with nitrogen gas, TAT (Turn Around Time) may be adversely affected. Further, there is a possibility that a moisture, an organic component, etc., will flow into the loading area S2.
This problem has been solved by JP 2004-6804A of the Applicant of this patent application. However, in JP 2004-6804A, since the container is pressed from above onto the table, it is difficult to apply the technique to a processing apparatus in which a sufficient room is difficult to be obtained above a container.
The present invention provides a processing apparatus and a processing method that solve the problems of the aforementioned conventional technique, and restrain a displacement of a container from an opening of a partition wall, while improving a resistance to a differential pressure between a pressure of a transfer area and a pressure of a carry-in area.